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General => The garage => Topic started by: Josho on 02 March 2009, 11:44

Title: What size fuse and relays for headlights?
Post by: Josho on 02 March 2009, 11:44
I'm thinking of going to Maplin and getting some relays and fuses to make an uprated loom for the headlights on the van and on the Golf.

What sort of ampage would I need? Thanks.
Title: Re: What size fuse and relays for headlights?
Post by: Josho on 02 March 2009, 13:30
Seen a guide 20AMP fuses.

Do that. I'm going to buy 4 relays I think and a few meters of wire.

That's one relay per light for high and low.

My idea is to take the stock headlight wires out of the bulb holder and put them to the relay.

Off to Maplin methinks.
Title: Re: What size fuse and relays for headlights?
Post by: Josho on 02 March 2009, 13:31
Oh, one question, ground, to battery or chassis, what's best?
Title: Re: What size fuse and relays for headlights?
Post by: rubjonny on 02 March 2009, 14:00
id go battery
Title: Re: What size fuse and relays for headlights?
Post by: Josho on 02 March 2009, 14:41
Sweet. Now ordering all parts off eBay as I can't find my card. It's all in my account.
Cheers Jonny!  :smiley:
Title: Re: What size fuse and relays for headlights?
Post by: Josho on 02 March 2009, 14:55
OK, my plan is:

10AWG from battery to project box that contains two relays. One for high one for low. Then take the harness out of left headlight, and use the high and low power cables to trigger the relays.

Then from the relay straight to a distribution block of some kind, still 10 or 12 AWG then distributed to 12AWG for both headlights, running above the radiator, to the right headlight.

Then grounding them to the battery.

See if it makes a difference, put it on the drive front ways to take comparison photos.
Title: Re: What size fuse and relays for headlights?
Post by: Teutonic_Tamer on 02 March 2009, 15:47
I'm thinking of going to Maplin and getting some relays and fuses to make an uprated loom for the headlights on the van and on the Golf.

What sort of ampage would I need? Thanks.

That would depend on what wattage bulbs you will be using.  If you want to use the rally spec 160 watt bulbs, then they will need a bigger fuse, ideally a remote relay, and some larger diameter wire.
Title: Re: What size fuse and relays for headlights?
Post by: Josho on 02 March 2009, 16:09
I'm thinking of going to Maplin and getting some relays and fuses to make an uprated loom for the headlights on the van and on the Golf.

What sort of ampage would I need? Thanks.

That would depend on what wattage bulbs you will be using.  If you want to use the rally spec 160 watt bulbs, then they will need a bigger fuse, ideally a remote relay, and some larger diameter wire.

Standard bulbs. No higher then 60W, keeping it legal.
Title: Re: What size fuse and relays for headlights?
Post by: Ben Lessani on 04 March 2009, 09:04
If you're running 60w - then its 60/12 = 5A, if its one wire for both sides, then 10A - allow some overhead 15A total.

For about a 6ft max length of wire, you're looking at 18 AWG @ 12V.

Personally, I'd ground off the chassis, its a spot neater and the voltage drop will be negliable, esp since its the alternator powering the bulbs, not the battery. Get some extra bits here (http://www.vehicle-wiring-products.eu/VWP-onlinestore/home/homepage.php)

More here (http://www.golfgtiforum.co.uk/index.php?topic=49436.msg410777#msg410777)
Title: Re: What size fuse and relays for headlights?
Post by: Teutonic_Tamer on 04 March 2009, 10:15
I suppose if the OP is keeping everything standard, why the need for rewiring then?  :huh:

Oh, and on cars earlier than a certain age, 100 watt bulbs are actully road legal too.  :wink:  And I have never been stopped when running 130w or 160w on some older cars I used to own - and I think you may also find that cop cars use very high wattage headlamp bulbs too.
Title: Re: What size fuse and relays for headlights?
Post by: Ben Lessani on 04 March 2009, 11:21
I suppose if the OP is keeping everything standard, why the need for rewiring then?  :huh:

3000 posts and you don't know about the voltage drop on the Golf?
Title: Re: What size fuse and relays for headlights?
Post by: Teutonic_Tamer on 04 March 2009, 12:12
I suppose if the OP is keeping everything standard, why the need for rewiring then?  :huh:

3000 posts and you don't know about the voltage drop on the Golf?

I DO know about voltage drops, in general.  But I wasn't aware of anything special with Mk3s!  :huh:  So are they particularly bad?  :undecided:
Title: Re: What size fuse and relays for headlights?
Post by: Ben Lessani on 04 March 2009, 14:03
Lol, no idea on a MK3 - I see Golf and assume MK2 :grin:
Title: Re: What size fuse and relays for headlights?
Post by: Josho on 04 March 2009, 19:47
Thanks guys. 92 Golf, 96 Golf and 94 van.

The T4's apparently work so much better with a new loom, so I was thinking of doing it. Want to do it on the Golf as one has 100w bulbs.

What years would be legal for 100w?

Thanks.
Title: Re: What size fuse and relays for headlights?
Post by: Ben Lessani on 04 March 2009, 19:58
I didn't think there was a law on watts, as long as they're E marked.

For an MOT I know its irrelevant, you could have 8000W bulbs in there as long as the beam pattern is correct.
Title: Re: What size fuse and relays for headlights?
Post by: Teutonic_Tamer on 10 March 2009, 16:54
Thanks guys. 92 Golf, 96 Golf and 94 van.

The T4's apparently work so much better with a new loom, so I was thinking of doing it. Want to do it on the Golf as one has 100w bulbs.

What years would be legal for 100w?

I think it was pre-1990 - but don't quote me on that.  Maybe try and look on the www.PowerBulbs.com site.
Title: Re: What size fuse and relays for headlights?
Post by: Teutonic_Tamer on 10 March 2009, 17:00
I didn't think there was a law on watts, as long as they're E marked.

There is a law on bulb wattages - just like there is a law on exhausts.  But ATEOTD, how many 'illegal' zorsts are ever picked up

For an MOT I know its irrelevant, you could have 8000W bulbs in there as long as the beam pattern is correct.

Agreed - but the MoT does not cover all aspects of automotive Construction and Use Regulations (CURs) - and it is that specific law which covers boring stuff light headlamp wattages.  :wink: